JPH05298747A - Optical information recording medium and designing method for structure thereof - Google Patents

Optical information recording medium and designing method for structure thereof

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Publication number
JPH05298747A
JPH05298747A JP9760692A JP9760692A JPH05298747A JP H05298747 A JPH05298747 A JP H05298747A JP 9760692 A JP9760692 A JP 9760692A JP 9760692 A JP9760692 A JP 9760692A JP H05298747 A JPH05298747 A JP H05298747A
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layer
recording medium
thin film
cry
recording
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JP3087433B2 (en )
Inventor
Nobuo Akahira
Kenichi Nishiuchi
Eiji Ono
Kenichi Osada
Noboru Yamada
鋭二 大野
昇 山田
健一 西内
信夫 赤平
憲一 長田
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Matsushita Electric Ind Co Ltd
松下電器産業株式会社
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Abstract

PURPOSE: To provide an optical information recording medium which has high CN ratio, high erasing ratio and which is overwritable with a single laser beam having a wide erasing power allowance.
CONSTITUTION: A dielectric layer 7, a recording layer 8, a dielectric layer 9 are sequentially laminated on a board 6, and two film surfaces are laminated on the inside through an adhesive layer. The layer 8 is formed of substance in which a reversible phase change between an amorphous phase and a crystalline phase. A reflecting layer 10 is formed of Au or an Au alloy thin film in such a manner that a film thickness is 15nm or less, and an optical calculation is executed by varying thicknesses of the dielectric layers 7, 9. Reflectivities of the recording layer from an absorption factor recording medium with an emitted laser light ray having a wavelength λ are A (amo), R (amo) in the amorphous state of the recording layer and A (cry), R (cry) in the crystalline state, and the thickness simultaneously satisfies two conditions of a difference ΔA≥5% of the absorption factors and a difference ΔR≥15% of the reflectivities between the two states.
COPYRIGHT: (C)1993,JPO&Japio

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【産業上の利用分野】本発明は、基板上に形成された相変化材料薄膜にレ−ザ−ビーム等の高エネルギービームを照射することにより信号品質の高い情報信号をオーバライトすることのできる書換え可能な光学的情報記録媒体の構成およびその構成方法に関する。 The present invention relates is a phase change material thin film formed on a substrate - capable of overwriting with a high signal quality information signal by irradiating a high energy beam such as a beam - The configuration and its configuration method rewritable optical information recording medium.

【0002】 [0002]

【従来の技術】基板上に形成したカルコゲナイド薄膜にレーザ光線を照射して局所的な加熱を行い、微小部分の光学的な特性(屈折率)を変化させることができることは光誘引性の相変化現象として既に知られている。 Perform local heating by irradiating a laser beam to the Prior Art chalcogenide thin film formed on a substrate, the phase change optical attractiveness that can change the optical properties of the minute portion (refractive index) It is already known as a phenomenon. 即ち、レーザ光線の照射条件を選べば照射部を原子結合状態が比較的乱れた状態(アモルファス相)から比較的整った状態(結晶相)、また反対に結晶相からアモルファス相へと高速に相変化させることが可能であり、高密度情報記録を行う方法の一つとして応用開発が行われてきた。 That is, the state in which the irradiation unit be selected irradiation conditions of the laser beam atomic bonding state is relatively well equipped from a relatively disordered state (amorphous phase) (crystalline phase), also a phase at high speed from the crystalline phase to the opposite to the amorphous phase it is possible to vary, is applied developed as a method for performing high-density information recording has been performed.

【0003】相変化記録のメリットの1つは、記録手段として単一のレーザビームのみを用い、情報信号をオーバライトできる点にある。 [0003] One of the advantages of phase change recording uses only a single laser beam as a recording unit, in that the information signal can be overwritten. すなわち、レーザー出力を記録レベルと消去レベルの2レベル間で情報信号に応じて変調し記録済みの情報トラック上に照射すると、既存の情報信号を消去しつつ新しい信号を記録することが可能である(特開昭56−145530号公報)。 That is irradiated onto modulates recorded information track in accordance with the information signal between two levels of the laser power recording level and erasure level, it is possible to record a new signal while erasing the existing information signal (JP-A-56-145530 JP). この方法は光磁気記録のように磁気回路部品が不要なことからヘッドが簡素化できる点、消去動作を必要としないため書換え時間を短縮することできる点が映像や音声信号の記録に有利と考えられ記録媒体の開発研究が進められている。 The method considered to be advantageous to the recording of the magneto-optical recording magnetic circuit components that can head simplified since unnecessary, the video and audio signals that can be to shorten the rewrite time because it does not require an erase operation as development of is recording medium has been developed.

【0004】オーバライトに特有の課題についても抽出が行われ、その解決策の提案がなされてきている。 [0004] also extracted for specific to overwrite task is carried out, it has been made proposals of their solutions. 例えばオーバライト時の消去率が消去動作のみを行った場合の消去率に比べて低くなるという課題があった。 For example the erasure rate during overwriting is a problem that is lower than the erase ratio in the case of performing only the erase operation. この課題に対して我々は特開平1−149238号公報において、アモルファス状態である記録マーク部における光吸収率と結晶状態である未記録部における光吸収率を同等にした記録媒体、及び結晶状態部での光吸収率をアモルファス状態部での光吸収率よりも大きくした記録媒体を提案した。 In our Japanese Patent Laid-Open 1-149238 discloses for this problem, the recording medium equal to the light absorption rate in the non-recorded portion is a crystalline state and optical absorptance of the recording mark portion in an amorphous state, and crystalline state portion the light absorption rate in the proposed recording medium is larger than the light absorption rate in the amorphous state portion. 即ち、図5に示すように表面の平滑な基板1 That is, smooth the surface of the substrate as shown in FIG. 5 1
の上に誘電体3でサンドイッチした記録層2を形成した媒体、及び誘電体3の上にさらに光反射層4を設け、保護板5を付けた構成の媒体において、主として誘電体層各層の厚さを適当に選ぶことで上記光吸収率に関する条件を満足する光記録媒体を形成し、この媒体ではオーバライト時の消去率が改善されることを開示した。 Medium to form a recording layer 2 which is sandwiched by the dielectric 3 on top of, and more light-reflective layer 4 on the dielectric 3 is provided, in the medium having the structure with a protective plate 5, mainly the dielectric layer thickness of each layer of the form an optical recording medium which satisfies the conditions relating to the light absorption rate in appropriately choosing it, in this medium is disclosed that erasure rate during overwriting may be improved.

【0005】しかしながら、この従来例における実施例の媒体の場合には反射率変化が十分大きいとは言えなかった。 However, reflectivity changes in the case of the medium of the examples in this prior art can not be said to be sufficiently large. 例えば3頁の実施例第2表において、アモルファス状態の吸収率が結晶状態の吸収よりも大きな媒体N For example, in Example Table 2, page 3, large medium N than the absorption of the absorption of the amorphous state is a crystalline state
o. o. 1、No. 1, No. 4が19.1%、16.4%という反射率変化を示すのに対して、結晶状態の方がアモルファス状態よりも吸収率の大きい媒体No. 4 is 19.1%, whereas showing reflectance variation of 16.4%, a large media absorptivity than the amorphous state towards the crystalline state No. 3、No. 3, No. 6は9.7%、11.2%と小さな反射率変化しか示さなかった。 6 9.7%, showed only 11.2% and a small reflectance change. 特に記録膜が40nmの場合には半分以下の値しか示していない。 Especially when the recording film is 40nm only it shows less than half of the value. 図6は、特開平1−149238号公報中に記載の実施例の結果をグラフ化したものであって、結晶部での光吸収率をA(cry)、アモルファス部での光吸収率をA(amo)とし、記録前後の2つの状態における光吸収率の差ΔA(=A(cry)−A(amo))とC/N Figure 6 is a a graph of the results of Examples described in JP-A-1-149238, the light absorption rate in the crystalline part A (cry), the light absorption rate in the amorphous portion A and (amo), the difference in the light absorption rate in the two states before and after recording ΔA (= a (cry) -A (amo)) and C / N
ならびに消去率の関係を示したものである。 And shows the relationship between the erasure rate. これによれば光吸収率の差ΔAが正方向に増加するに従って消去率が改善されていること、一方C/Nはわずかづつではあるが低下していることが分かる。 According to this the erasure rate is improved according to the difference ΔA of the light absorption factor increases in the positive direction, it can be seen that there has been reduced in the meantime C / N HawazuKazutsu. この場合のC/N低下の原因は、図7によって明らかである。 Cause of C / N drop in this case is apparent from FIG.

【0006】図7は、図6と同じく特開平1−1492 [0006] FIG. 7, like JP-as in FIG. 6 1-1492
38号公報中に記載の実施例の結果をグラフ化したものであって、結晶部での光吸収率をA(cry)、反射率をR A a graph of the results of Examples described in 38 discloses a light absorption rate in the crystalline part A (cry), the reflectance R
(cry)、アモルファス部での光吸収率をA(amo)、反射率をR(amo)とし、記録前後の2つの状態における光吸収率の差ΔA(=A(cry)−A(amo))と反射率変化量ΔR (Cry), the light absorption rate in the amorphous portion A (amo), the reflectance and R (amo), the difference in the light absorption rate in the two states before and after recording ΔA (= A (cry) -A (amo) ) and the reflectance change amount ΔR
(=R(cry)−R(amo))の関係を示したものである。 It shows the relationship between (= R (cry) -R (amo)). これによれば、従来例の記録媒体では光吸収率の差ΔAが増加するにしたがって反射率変化量ΔRは一方向的に減少しており、オーバライト時の消去率と信号振幅とは相反する関係にあったことが分かる。 According to this, reflectance change amount ΔR according to the difference ΔA of the light absorption rate is increased in the recording medium of the prior art are reduced unidirectionally, contrary to the erase ratio and the signal amplitude at the time of overwrite it can be seen that there was a relationship.

【0007】別の従来例としては特開平3−11384 [0007] Another Patent as prior art 3-11384
4号公報は反射層を用いない媒体構造で、かつ記録膜が80nmと厚い構成の媒体を開示している(3ページ第1表)。 4 No. in media construction without a reflective layer, and the recording film discloses a medium 80nm and thicker structure (3 pages Table 1). この場合は、しかしながら、この場合には結晶部の光吸収率がアモルファス部の吸収率に比べて十分大きいできる媒体条件が開示されていない。 In this case, however, the medium conditions that can sufficiently larger than the light absorption rate of the crystal portion in the absorption rate of the amorphous portion in this case is not disclosed. 例えば、アモルファス部の吸収率が結晶部よりも10%以上大きい構成の開示はあるが、結晶部の吸収率がアモルファス部より大きい媒体では、その差は高々2.1%であり、融解潜熱の差をキャンセルするには不十分であった。 For example, although the absorption of the amorphous portion is disclosed in greater structure by 10% or more than the crystal unit, a medium absorption rate is greater than the amorphous portion of the crystal portion, the difference is at most 2.1%, the latent heat of fusion It was insufficient to cancel the difference.

【0008】 [0008]

【発明が解決しようとする課題】アモルファス状態である記録マーク部と結晶状態である非記録マーク部の両部における光吸収率差ΔAに留意した上記従来例(特開平1−149238号公報)に開示された記録媒体ではオーバライトモード記録における消去率の向上が実現されたが、その一方では図7に示されたように、記録前後の反射率変化量ΔRが小さくなっていた。 In the conventional example noted light absorptivity difference ΔA in both parts of the non-recording mark portion which is a recording mark portion crystalline state is an amorphous state [0006] (JP-A-1-149238) Although improvement in erasing ratio at overwriting mode recording is disclosed a recording medium is achieved, on the other hand, as shown in FIG. 7, reflectance change amount ΔR before and after recording was smaller. 反射率変化量Δ Reflectance change amount Δ
Rは信号の大きさそのものであるから、基本的にはΔR Since R is the signal magnitude itself is basically ΔR
が小さくなればC/Nも低下する。 The C / N is also reduced if smaller. この時、従来例の場合のように、記録マークピッチが2μm以上(線速度1 At this time, as in the conventional example, the recording mark pitch is 2μm or more (linear speed 1
5m/s,記録周波数7MHzから計算可能)といった記録条件では、形成される記録マーク部の面積はレーザスポットに比較して十分大きくなるから、ΔRが多少小さくても全体として大きな反射光量の変化が生じ大きなC/Nが得られるが、マークピッチをもっと詰めて記録密度を高めようという場合には同様ではない。 5 m / s, the recording conditions, such as computable) from the recording frequency 7 MHz, since the area of ​​the recording mark portion formed is sufficiently larger than the laser spot, a large change in reflected light as a whole ΔR is also slightly smaller large C / N occurs is obtained, but not the same as in the case of trying to increase the recording density by more packed mark pitch. この場合には、記録マークの大きさがレーザスポットの大きさと同等およびそれ以下に小さくなるからΔRが小さければ、それだけ小さな反射光量変化しか得られなくなり、 In this case, if ΔR is smaller because the size of the recording mark becomes small magnitude equal and below and of the laser spot, can not be obtained only much smaller amount of reflected light changes,
ΔR低下の影響がそのままC/Nの大きな低下となって現れる。 Influence of ΔR decline appears as it is a major decrease in the C / N. 即ち、高密度記録を行うという前提ではオーバライト時におけるC/Nと消去率とを同時に満足できる記録媒体は未だ実現されていなかったと言える。 That is, it can be said that a high density recording medium capable of satisfying the C / N and erase ratio at overwriting simultaneously assuming that the recording performing has not been realized yet.

【0009】別の課題としては、従来相変化記録媒体に用いられてきたマーク位置記録(あるいはPPM記録) [0009] As another problem, the conventional phase change recording medium mark position recording that has been used (or PPM recording)
方式をマークエッジ記録(あるいはPWM記録)方式に置き換えるためにはより高い消去率が必要になるということである。 Method is that require a higher erasure rate is to replace the mark edge recording (or PWM recording) scheme. マーク位置記録では記録マークの形状が多少歪んでいてもピーク位置さえ検出できればエラーにならないが、マーク位置記録では形状の歪がそのままエラーになる。 Although not an error if detected even peak position be distorted somewhat the shape of a recording mark in the mark position recording, it becomes an error distortion shape in mark position recording. この場合には例えば磁気記録の場合と同様、 As with the case of the example magnetic recording in this case,
26dB程度の消去率をクリアーする必要がある。 It is necessary to clear the erasure rate of about 26dB.

【0010】本発明の目的は、記録マーク長がレーザスポットの大きさに近い高密度信号のオーバライト記録を行っても、C/N及び消去率がともに大きいこと、あるいはマークエッジ記録に適合する大きな消去率が得られることを目指し、上記ΔA,ΔRがいずれも十分大きく、少なくともΔA≧5%、ΔR≧15%を同時に満足する記録媒体を提供するものである。 An object of the present invention, even if the overwrite recording high-density signals near the recording mark length is the size of the laser spot, conforms to C / N and erase ratio are both large or mark edge recording aim a large erasure rate is obtained, the .DELTA.A, both [Delta] R is sufficiently large, there is provided a recording medium which satisfies at least ΔA ≧ 5%, ΔR ≧ 15% at the same time. また本発明のもう1つの目的は上記記録媒体を構成する方法を提供するものである。 Further another object of the present invention is to provide a method for forming the recording medium.

【0011】 [0011]

【課題を解決するための手段】本発明は基板上に少なくとも第1の誘電体薄膜層、波長λのレーザ光線を照射することにより可逆的構造変化を生じ、光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層、第2の誘電体薄膜層および光反射層を積層して成る光学的情報記録媒体において、上記反射層をAuまたはAuを主成分とする合金薄膜で構成し、その厚さを15nm以下とする。 The present invention SUMMARY OF THE INVENTION At least the first dielectric thin film layer on a substrate results in a reversible structural change by irradiation with a laser beam of wavelength lambda, the optical constants (refractive index n, extinction recording layer comprising a reversibly changing phase change material thin film optical properties between the amorphous state coefficient k) is relatively small and the crystalline state is relatively large, the second dielectric thin film layer and the optical information recording medium comprising a light-reflecting layer are laminated, the reflective layer is made of an alloy film mainly composed of Au or Au, to a thickness of between 15nm or less.

【0012】その上で記録層の厚さd0、上記第1および第2の誘電体薄膜層の厚さd1,d2をそれぞれ独立に様々に仮定して、マトリクス法により上記記録膜がアモルファス状態にある場合、結晶状態にある場合の反射率、吸収率をそれぞれ算出し、上記条件を満たすd0、 [0012] The thickness of the recording layer on its d0, the various assuming the first and second dielectric thin film layer thickness d1, d2 and independently, to the recording layer amorphous state by matrix method some cases, the reflectance when in the crystalline state, the absorption rate was calculated, the condition is satisfied d0,
d1、d2の組合せを決定する。 d1, to determine the combination of d2.

【0013】 [0013]

【作用】上記4層構成の光学的情報記録媒体においては入射光Iの行方は記録層で吸収されて熱に変わる部分(A)、反射層に吸収されて熱に変わる部分(L)、媒体表面で反射される部分(R)、媒体を通過してしまう部分(T)の4つにおおよそ分けることができる。 [Action] whereabouts of the incident light I in the optical information recording medium of four-layer structure portions vary absorbed in the recording layer to heat (A), is absorbed in the reflective layer are in part converted into heat (L), medium portion that is reflected by the surface (R), can be divided roughly into four parts (T) which would pass through the media. ここで記録層に吸収される光量は記録層がアモルファス状態である時と結晶状態である時とで異なり、各々A(amo) Amount of light absorbed in the recording layer where the different between when the recording layer is in a crystalline state as when in an amorphous state, respectively A (amo)
=I−[L(amo)+R(amo)+T(amo)]、A(cry)=I− = I- [L (amo) + R (amo) + T (amo)], A (cry) = I-
[L(cry)+R(cry)+T(cry)]となる。 A [L (cry) + R (cry) + T (cry)]. つまりアモルファス部と結晶部の間の光吸収率差は、ΔA=A(cry) Light absorptance difference between words and the amorphous portion crystal part, ΔA = A (cry)
−A(amo)=[R(amo)−R(cry)]+[L(amo)−L(cr -A (amo) = [R (amo) -R (cry)] + [L (amo) -L (cr
y)]+[T(amo)−T(cry)]、即ちΔA=ΔL+ΔT− y)] + [T (amo) -T (cry)], ie ΔA = ΔL + ΔT-
ΔR(ΔL=L(amo)−L(cry)、ΔT=T(amo)−T(cr ΔR (ΔL = L (amo) -L (cry), ΔT = T (amo) -T (cr
y)、ΔR=R(cry)−R(amo))と表わされる。 y), is expressed as ΔR = R (cry) -R (amo)). ここで、 here,
例えばΔR≧15%を確保し、なおかつΔA≧5%を確保するためには右辺第1項(反射層での吸収率差)と第2項(透過率差)の合計で20%以上の差を確保すればよいことになる。 For example ensuring ΔR ≧ 15%, yet the difference in total more than 20% of the second term (differential transmission) (absorption index difference in the reflection layer) the first term in order to ensure a .DELTA.A ≧ 5% it is sufficient to ensure.

【0014】本発明ではAu反射層またはAuを主成分とする合金反射層の厚さを15nmよりも薄くすることで上記条件を達成した。 [0014] The present invention has achieved the above conditions by thinner than 15nm thick of alloy reflective layer mainly composed of Au reflective layer or Au. 理由は以下の通りである。 The reason is as follows. 即ち、反射層を光が透過しない程度に厚くすると記録層の状態によらず、媒体を透過してくる光は小さくなり、透過率T(amo)、T(cry)ならびにそれらの差ΔTも当然零に近づく。 That is, regardless of the light reflective layer is thick enough to not transmit the state of the recording layer, becomes small light transmitted through the medium, the transmittance T (amo), T (cry) and naturally also their difference ΔT it approaches zero. またAuは反射率が大きいので反射層での吸収も10%以下でありΔLは当然、それ以下になる。 The Au course is absorbed is 10% or less ΔL in the reflective layer because a large reflectivity, becomes less. 従って、記録層における光吸収率の絶対量を大きくするために反射層を厚くすれば必然的にΔA≒−ΔRとなり本発明の目的とするところは果たせなくなる。 Thus, no longer fulfill It is an object of the inevitably .DELTA.A ≒ - [Delta] R next to the present invention if thick reflective layer in order to increase the absolute amount of light absorption rate in the recording layer. 本発明の光学的情報記録媒体では反射層の厚さと反射率、吸収率の関係を調べ、厚さが15nm以下で有れば適度な透過率と反射層への吸収率が得られ、結果として実用的に十分広い膜厚誤差許容幅をもって上記、目的が満たされることを見いだしたものである。 Thickness and reflectivity of the reflective layer in the optical information recording medium of the present invention to examine the relationship between the absorptance, moderate transmittance and absorptance of the reflective layer is obtained if there thickness in 15nm or less, as a result It has practically sufficiently wide thickness error tolerance in which found that above purpose are met. AuまたはAuを主成分とする合金は他の金属と比較して化学的にはるかに安定であり、15nm以下という極薄膜としても十分機能を発揮できるというメリットを有している。 An alloy mainly containing Au or Au is chemically much more stable as compared with other metals, have the advantage that also exhibit a sufficient function as a very thin film of 15nm or less.

【0015】 [0015]

【実施例】本発明の代表的な光学情報記録媒体は、図1 EXAMPLES representative optical information recording medium of the present invention, FIG. 1
に示すように基板6の上に第1の誘電体薄膜層7、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層8、第2の誘電体薄膜層9、AuまたはAuを主成分とする合金から成る光反射層10を順次積層して形成し、 The first dielectric thin film layer 7, the optical constants of the above wavelength λ by irradiation of a laser beam (refractive index n, extinction coefficient k) of the wavelength λ is relatively large as on the substrate 6 shown in recording layer 8 made of reversibly changing the phase change material thin film optical properties between the crystalline state and the amorphous state is relatively small, and mainly of the second dielectric thin film layer 9, Au or Au the light reflecting layer 10 made of an alloy are sequentially laminated to form,
基板側から記録再生のためのレーザ光線11を入射させる。 From the substrate side is incident laser beam 11 for recording and reproduction. 図1ではホットメルトタイプの接着層12を介して上下対称になるように2枚が張り合わせた構成になっているが、図2のように第2の誘電体薄膜層の上にUV樹脂等の保護層13を形成した単板構造も可能である。 Although two has a configuration in which laminated so as to be vertically symmetrical with an adhesive layer 12 in FIG. 1, the hot melt type, such as UV resin on the second dielectric thin film layer as shown in FIG. 2 veneer structure to form a protective layer 13 are possible. 図3のように基板の上に光反射層10、第2の誘電体層9、記録層8、第1の誘電体層7を積層し、第1の誘電体層側から光を入射させることも可能である。 Light reflecting layer 10 on the substrate as shown in FIG. 3, the second dielectric layer 9, the recording layer 8, the first dielectric layer 7 is laminated, that light is incident from the first dielectric layer side it is also possible.

【0016】基板6に用いる材料としては通常光ディスク等に用いられているPMMA、ポリカーボネイト、アモルファスポリオレフィン等の透明樹脂板、ガラス板、 [0016] PMMA as a material used for the substrate 6 used in the normal optical disk or the like, polycarbonate, a transparent resin plate such as amorphous polyolefin, glass plate,
Al,Cu等の金属板あるいはこれらをベースにした合金板を用いる。 Al, using a metal plate or alloy plate These were based, such as Cu. 不透明な基板を用いる場合には図3の構成に準じる必要がある。 When using an opaque substrate, it is necessary to conform to the configuration of FIG. また、光ディスクの用途では記録再生に用いるレーザ光線を導くために表面にはサブミクロンサイズの幅、深さを持った同芯円またはスパイラル状の連続溝、あるいはピット列が凹凸で刻まれているのが通常である。 The width of the sub-micron size on the surface to direct the laser beam, a concentric circle or spiral continuous groove with a depth or pit row, is engraved with irregularities used for recording and reproduction in applications of the optical disc the is normal.

【0017】上下2層の誘電体層7,9は樹脂の基板を用いる場合には基板6の表面の熱ダメージを抑える働きとともに相変化材料層8を挟み込むことで膜の変形、蒸発を抑える等の働きをなすものであって、樹脂、記録膜材料と比較して融点の高いこと、記録再生に用いるレーザ光線に対して透明であること、硬度が大きくて傷がつきにくいこと等の性質を有することが必要である。 The upper and lower dielectric layers 7 and 9 of the two-layered film deformation by sandwiching a phase-change material layer 8 with help decrease the thermal damage on the surface of the substrate 6 in the case of using a substrate of resin, such as suppressing the evaporation be those that form the function of the resin, higher melting point as compared with the recording film material, it is transparent to the laser beam used for recording and reproduction, the properties such that the scratch-resistant large hardness it is necessary to have. 例えば、SiO 2 ,ZrO 2 、TiO 2 ,Ta 25等の酸化物、BN、Si 34 ,AlN,TiN等の窒化物、Zn For example, SiO 2, ZrO 2, TiO 2, Ta oxides such 2 O 5, BN, Si 3 N 4, AlN, nitride such as TiN, Zn
S,PbS等の硫化物、SiC等の炭化物、CaF 2等のフッ化物、ZnSe等のセレン化物及びこれらの混合物としてZnS−SiO 2 、SiNO等、あるいはダイヤモンド薄膜、ダイヤモンドライクカーボン等を用いることができる。 S, sulfides such as PbS, carbides such as SiC, fluorides such as CaF 2, selenide ZnSe, etc., and ZnS-SiO 2, SiNO such as a mixture thereof, or a diamond thin film, the use of diamond-like carbon it can.

【0018】本発明で記録層8に用いる材料は相変化物質薄膜の中でもレーザ光線の照射でアモルファス−結晶間の可逆的相変態を生じるものであって、結晶状態ではアモルファス状態よりも大きな屈折率、消衰係数を示すものを用いる。 [0018] The present invention amorphous irradiation of the laser beam among the materials the phase change material thin film used for the recording layer 8 - be those in which a reversible phase change between crystal, higher refractive index than the amorphous state in the crystalline state , used indicates the extinction coefficient. 代表的にはGe−Sb−Te,Ge−T Typically Ge-Sb-Te, Ge-T
e,In−Sb−Te,Sb−Te,Ge−Sb−Te e, In-Sb-Te, Sb-Te, Ge-Sb-Te
−Pd,Ag−Sb−In−Te,Ge−Bi−Sb− -Pd, Ag-Sb-In-Te, Ge-Bi-Sb-
Te,Ge−Bi−Te,Ge−Sn−Te、Ge−S Te, Ge-Bi-Te, Ge-Sn-Te, Ge-S
b−Te−Se,Ge−Bi−Te−Se、Ge−Te b-Te-Se, Ge-Bi-Te-Se, Ge-Te
−Sn−Au等の系、あるいはこれらの系に酸素、窒素等の添加物を加えた系を用いることができる。 -sn-Au or the like of the system or oxygen in these systems, can be used additives a system was added, such as nitrogen. これらの薄膜は通常成膜された時はアモルファス状態であるが、 These films are amorphous state when normally deposited,
レーザ光線等のエネルギーを吸収して結晶化し光学的濃度が高くなる。 Optical density was crystallized by absorbing energy such as a laser beam is increased. 実際に記録媒体として用いる場合には記録膜面の全体を予め結晶化しておき、レーザ光線を細く絞って照射し、照射部をアモルファス化して光学定数を変化させる。 Advance crystallize the entire recording film surface in the case of using as an actual recording medium, by irradiating a laser beam narrow squeezed, to change the optical constants and amorphous irradiation unit. 上記変化は、上記記録膜にさらに変化を与えない程度に弱くしたレーザ光線を照射し、反射光の強度変化、透過光の強度変化を検出して情報を再生する。 The change irradiates a laser beam that is weak enough not give more change in the recording film, the intensity change of the reflected light, by detecting changes in the intensity of the transmitted light to reproduce information.
本発明は記録前後の記録部と、非記録部の光学的特性の関係を一定条件になるべく媒体構成することでオーバライト特性の向上を図るというもので、本来記録層の組成に縛られるものではない。 The present invention is a recording unit of before and after recording, the relationship between the optical properties of the non-recording portion intended that improve the overwrite characteristic as much as possible to configure the medium constant conditions, the present invention is tied to the composition of the original recording layer Absent. 従って、ある代表的組成が本発明に適用できればその組成に多少の添加物を加えた組成物もまた適用可能である。 Therefore, the composition is representative composition plus some additives to the composition if applied to the present invention may also be applicable.

【0019】記録層8の厚さは、記録層8が結晶状態にある時でも入射光線の一部が記録層8を透過可能な厚さに選ぶ。 [0019] The thickness of the recording layer 8, a part of the incident light, even when the recording layer 8 is in a crystalline state chooses recording layer 8 into a permeable thickness. 例えば上記相変化材料膜(結晶相)を誘電体薄膜層7,9と同じ材質の誘電体層(厚さは無限と仮定) For example the phase change material film dielectric layer of the same material (crystal phase) and dielectric thin film layers 7 and 9 (assuming the thickness infinite as)
に挟まれた時の透過率を考え、その値が少なくとも1% The transmittance when sandwiched considered, the value is at least 1%
程度以上、好ましくは2〜3%程度以上あること、またその値は上記相変化材料膜がアモルファス相である場合に比較して10%程度以上であることが望ましく、そうなるべく各膜厚を選ぶことが重要である。 Degree or more, preferably it is more than 2 to 3%, and it is desirable that the value is at least about 10% as compared to the case where the phase change material film is an amorphous phase, choosing the right as much as possible the respective film thickness This is very important. 反射層10で反射されて記録層8中に再入射する成分が無くなると光の干渉効果が小さくなり、第2の誘電体薄膜層9ならびに反射層10の膜厚を多少変化させても媒体全体の反射率、記録層での吸収等を制御できなくなる。 When components to be re-incident on the recording layer 8 is reflected by the reflecting layer 10 is eliminated light interference effect becomes small, the whole medium is also slightly changing the thickness of the second dielectric thin film layer 9 and the reflective layer 10 reflectance, can not be controlled absorption, etc. of the recording layer.

【0020】図4は代表的な記録膜組成としてGe 2 [0020] Figure 4 is a representative recording film composition Ge 2 S
2 Te 5をZnS−SiO 2混合物(SiO 2 :20モル%)膜で挟んだ時の膜厚と透過率(波長780nm)の関係を示したものである。 b 2 Te 5 a ZnS-SiO 2 mixture: shows a (SiO 2 20 mol%) film thickness and transmittance when sandwiched between membrane (wavelength 780 nm) relationship. 図から結晶状態の場合、膜厚が60nm以下で有れば1%以上、50nm以下であれば2%以上、40nm以下であれば3%以上の透過率があることが分かる。 For crystalline state from FIG, 1% or more if there thickness in 60nm or less, 2% or more as long as 50nm or less, there can be seen that more than 3% transmittance as long 40nm or less.

【0021】反射層10に用いる金属薄膜としてはAu [0021] The metal thin film used in the reflective layer 10 Au
が最も適しているが、それ以外にもAuに添加物を加えた合金を用いることができる。 Although but it is most suitable, an alloy obtained by adding additives to the Au besides that. 添加物としてはAl,C The additive Al, C
r,Cu,Ge,Co,Ni,Ag,Pt,Pd,C r, Cu, Ge, Co, Ni, Ag, Pt, Pd, C
o,Ta,Ti,Bi,Sb、Mo等の材料群から選ばれる少なくとも1種を用いて熱伝導率、光学定数等の特性を微調整することができる。 o, Ta, Ti, Bi, Sb, thermal conductivity by means of at least one selected from the group of materials such as Mo, it is possible to fine-tune the characteristics such as optical constants. 例えばCrを加えると反射率はやや低下するが熱伝導度が大きく低下し、感度を向上することができた。 For example, the reflectance adding Cr decreased slightly lowered high thermal conductivity, it is possible to improve the sensitivity. また、Mo,Cr等の添加は誘電体層との接着強度を向上させた。 Further, Mo, the addition of Cr or the like is improved the adhesion strength between the dielectric layer.

【0022】第1及び第2の誘電体薄膜層7,9の膜厚は以下のように決定される。 The thickness of the first and second dielectric thin film layers 7 and 9 is determined as follows. まず、各層を構成する物質の複素屈折率を通常の方法(例えばガラス板上に薄膜を形成し、その膜厚と反射率、透過率の測定値を元に計算する方法、あるいはエリプソメーターを使う方法)で求める。 First, the complex refractive index of the material constituting each layer thin film is formed on the conventional method (for example, a glass plate, using a film thickness and the reflectivity, the method for calculating based on the measured values ​​of transmittance or an ellipsometer, determined by the way). 次に、記録層7および反射層9の厚さを固定した上でマトリクス法(例えば久保田広著「波動光学」岩波書店、1971年、第3章を参照)によって第1及び第2の誘電体の膜厚を計算により求める。 Next, the recording layer 7 and the matrix method in terms of the thickness of the reflective layer 9 and fixed (e.g. Hiroshi Kubota et al., "Wave Optics", Iwanami Shoten, 1971, Chapter 3) first and second dielectric by determining the thickness of the calculations. 具体的には、各層の膜厚を仮定して表面を含む全ての界面に対してエネルギー保存則に基づき光エネルギーの収支を計算する。 Specifically, to calculate the balance on the basis of light energy on the energy conservation law for all interfaces including the surface assuming a film thickness of each layer.
即ち、多層媒体での各界面についてこのエネルギー収支の方程式をたて、得られた連立方程式を解くことで、入射光に対する透過光の強度、反射光の強度ならびに各層での吸収量を求めることができる。 That is, vertical equation of the energy balance for each interface in the multilayer medium, by solving the resulting system of equations, the intensity of the transmitted light to incident light, is possible to determine the absorption in the intensity of the reflected light and the layers it can. 記録膜が結晶状態にある時とアモルファス状態にある時のいずれの場合についても上記計算を行うことにより、記録前後の反射率変化ΔR、吸収差ΔAを知ることができる。 By recording film performs the calculations for cases when in the amorphous state when in a crystalline state, it is possible to know before and after recording reflectance change [Delta] R, the absorption difference .DELTA.A. 2つの状態間での反射率の差がなるべく大きく(≧15%)、結晶状態の吸収がアモルファス状態の吸収よりも5%以上大きい膜厚条件を選ぶ。 Is as large as possible a difference in reflectance between two states (≧ 15%), the absorption of the crystalline state chooses larger thickness condition 5% or more than the absorption of the amorphous state.

【0023】本発明の書換え可能な光学的情報記録媒体は通常の光学薄膜を形成する場合と同様に真空蒸着、マグネトロンスパッタリング、DCスパッタリング、イオンビームスパッタリング、イオンプレーティング等の方法で各層を順次積み重ねて行く方法で形成することができる。 The rewritable optical information recording medium of the present invention is a vacuum vapor deposition similarly to the case of forming the conventional optical thin film, magnetron sputtering, DC sputtering, ion beam sputtering, sequentially stacked layers by a method such as ion plating it can be formed by a method go. 記録媒体が設計通りにできているかどうかはできあがった媒体の反射率、透過率をスペクトルメーターを用いて測定し、予め計算した値と比較することで検証することができる。 Reflectivity of the recording medium is finished Whether made as designed medium, the transmittance was measured using a spectrometer, it can be verified by comparing the pre-calculated values. この場合、記録膜での吸収と、反射層での吸収を直接測定することはできないが、2またはそれ以上の波長で同じ比較を行うことで精度を高めることができる。 In this case, the absorption in the recording film, can not be measured directly absorbed in the reflective layer, it is possible to enhance the accuracy by performing the same comparison with two or more wavelengths. 以下、具体例をもって本発明をさらに詳しく説明する。 Hereinafter, details of this invention are described with specific examples.

【0024】(実施例1)1つの真空チャンバー中に直径100mmターゲットに対応する4つのカソードを備えたスパッタ装置を用い、上述の計算に基づいてレーザ波長780nmに対応する記録媒体を5枚作成した。 [0024] (Example 1) using a sputtering apparatus provided with four cathodes corresponding to the diameter 100mm target in one vacuum chamber, created 5 sheets of recording medium corresponding to the laser wavelength 780nm based on the above calculation 。 基板の材質はポリカーボネイトで、サイズは外径300m The material of the substrate is polycarbonate, size outer diameter 300m
m、内径35mm、厚さ1.2mmとした。 基板の表面はピッチ1.3μm、深さ60nm、幅0.6μmの連続溝で覆われている。 The surface of the substrate pitch 1.3 .mu.m, depth 60 nm, is covered by a continuous groove width 0.6 .mu.m. この溝のある面に以下のように誘電体膜、相変化記録膜を形成した。 The dielectric film as follows on a surface of the groove, thereby forming a phase change recording film.

【0025】各媒体は第2の誘電体層の厚さ以外はほぼ同様な構成をしている。 [0025] Each media has a similar construction except the thickness of the second dielectric layer.第1の誘電体層は厚さ93nm
のZnS−SiO 2 (SiO 2 :20モル%)混合物膜、 Of ZnS-SiO 2 (SiO 2: 20 mol%) mixture layer,
記録層は厚さ40nmのGe 2 Sb 2 Te 5膜、反射層は厚さ10nmのAuである。 Ge 2 Sb 2 Te 5 film of the recording layer thickness 40 nm, the reflective layer is Au having a thickness of 10 nm. 第2の誘電体層はZnS− The second dielectric layer ZnS-
SiO 2 (SiO 2 :20モル%)混合物膜であり、厚さは128nm、139nm、151nm、162nm、 SiO 2 (SiO 2: 20 mol%) and a mixture film, thickness 128 nm, 139 nm, 151 nm, 162 nm,
174nmとした。 It was 174nm. それぞれ吸収率差ΔAおよび反射率差ΔRの異なる媒体となっている(表1)。 Has a different medium with each absorptivity difference ΔA and the reflectance difference [Delta] R (Table 1). 各値は計算によって求めた。 Each value was determined by calculation.

【0026】 [0026]

【表1】 [Table 1]

【0027】スパッタガスはいずれもアルゴンを用い、 [0027] Both sputtering gases used were argon,
ガス圧を3mTorrとした。 The gas pressure was 3mTorr. 誘電体はRFスパッタを用い、300Wのパワーで毎分10nmの堆積速度で成膜した。 Dielectrics using an RF sputtering, was formed at a deposition rate per minute 10nm in power of 300 W. また記録層にはDCスパッタを用い、100W The use of a DC sputtering on the recording layer, 100W
のパワーで毎分10nmの速度で成膜を行った。 The film formation at a rate of 10nm was carried out at the power.

【0028】(表2)は上記5種類の媒体の反射率と透過率を記録層が結晶層である場合と、アモルファス相である場合の両方について調べた結果であり、計算値とスペクトロメータによる実測値を示したものである。 [0028] (Table 2) shows the results recording layer reflectance and transmittance of the five types of media examined for both the case of the crystal layer, when an amorphous phase, by the calculated value and spectrometer It shows the measured values. いずれの媒体においても計算値と実測値とはよく一致していることが分かる。 It can be seen that good agreement is also calculated and measured values ​​in any of the media. また、上下2つの評価ら求めたΔRの値は計算値とよく一致しており、試作した記録媒体はほぼ設計通りの光学特性を有していることが確かめられた。 The value of the upper and lower two evaluation prompted the ΔR are in good agreement with the calculated value, a recording medium prototype it was confirmed to have an optical characteristic substantially as designed. これより、No. Than this, No. 2,3は本発明の範囲内の記録媒体と見なせる。 2 and 3 can be regarded as a recording medium within the scope of the present invention.

【0029】 [0029]

【表2】 [Table 2]

【0030】(実施例2)実施例1のディスクを各2枚用意し、膜のついた面を内側にしてホットメルト接着剤を用いて張り合わせた。 [0030] (Example 2) The disc of Example 1 were prepared two each, bonded together with a hot melt adhesive to the marked surface of the membrane on the inside. 各ディスクを毎分1800回転で回転し、最外周部(線速度27m/s)でオーバライト特性を評価した。 Rotating each disk per minute 1800 rpm for evaluating overwrite characteristics at the outermost peripheral portion (a linear velocity of 27m / s). 記録信号はマークエッジ記録を想定して17.5MH(f1)および6.5MH(f2)の単一周波数信号とし、波長780nmの半導体レーザ光線をN. Recording signal assumes a mark edge recording the single frequency signal 17.5MH (f1) and 6.5MH (f2), N. a semiconductor laser beam having a wavelength of 780nm A. A. 0.55の対物レンズを用いて記録した(デューティー50%)。 It was recorded using a 0.55 of the objective lens (50% duty). 測定手順は、まずf1を記録してCN比を測定した後、f2をオーバライトしてf1 Measurement procedure, after measuring the CN ratio is first recorded f1, by overwriting the f2 f1
成分の減衰比を測定し消去率を測定する方法によった。 Measuring the attenuation ratio of the components was by the method of measuring the erasing ratio.
(表2)はCN比が50dBに到達するピークパワー(測定限界30mW)、CN比の飽和値、消去率の最大値及び消去率が26dBを越えるバイアスパワー域を示したものである。 (Table 2) are those peaks CN ratio reaches 50dB power (measurement limit 30 mW), the saturation value of the CN ratio, the maximum value and the erasure ratio of the erase ratio showed a bias power range exceeding 26 dB. この(表3)と(表1)から以下のことが分かった。 This was found to be as follows from (Table 3) and (Table 1).

【0031】即ち、(表1)のΔR、ΔAは(表3)のCN比、消去率およびバイアスパワーマージンとそれぞれ強い相関性を有しており、ΔAが5%に満たない場合には消去率26dBを越えるバイアスパワー領域がないことが示された。 [0031] That is, [Delta] R (Table 1), .DELTA.A has a CN ratio, the erasure ratio and bias power margin and each strong correlation (Table 3), erasure if .DELTA.A is less than 5% it has been shown no bias power region exceeding the rate 26 dB. これは結晶部とアモルファス部で同等の昇温を実現するためには、結晶部ではアモルファス部よりも融解潜熱に相当する分だけより大きなエネルギーを必要とするということであって、それがΔAの5%程度に相当することを示すのであろう。 This is in order to achieve a comparable Atsushi Nobori in the crystalline portion and the amorphous portion is crystalline portion is a that it requires a large energy than the amount corresponding to the latent heat of fusion than the amorphous portion, it is a ΔA it would indicate that corresponding to approximately 5%. またCN比で50 Also 50 in CN ratio
dB以上を得るためにはΔRが15%以上は必要であることが示された。 To obtain a more dB is ΔR has shown that 15% or more is necessary.

【0032】即ち、本発明の記録媒体(No.2,N [0032] That is, the recording medium of the present invention (No.2, N
o. o. 3)は50dBを越えるCN比と消去率26dBを越える広いパワー域を有することが示された。 3) it has been shown to have a broad power range exceeding erasure ratio 26dB and CN ratio greater than 50 dB.

【0033】 [0033]

【表3】 [Table 3]

【0034】(実施例3)実施例1、2と同様にポリカーボネイト基板、ZnS−SiO 2混合物薄膜、Ge 2 [0034] (Example 3) Similarly polycarbonate substrate as in Example 1,2, ZnS-SiO 2 mixture film, Ge 2 S
2 Te 5薄膜を用いて波長780nmを前提に各種記録媒体を試作し、その特性を評価した。 Various recording media fabricated assumes wavelength 780nm with b 2 Te 5 thin film, and its characteristics were evaluated. 記録膜の厚さは2 The thickness of the recording film 2
0nmから80nm、反射層の膜厚を3nmから50n 50n 80 nm, the thickness of the reflective layer from 3nm from 0nm
mまで振った。 It shook up to m. (表4)は設計試作した記録媒体についての特性評価結果を示す。 (Table 4) shows the characterization results for the recording medium the prototype design. 表中、○印はΔR≧15%かつΔA≧5%を満足する上下2層の誘電体層の膜厚条件が十分広い膜厚域(例えば±5%以上)をもって存在すること、△印はΔR≧15%かつΔA≧5%を満足する誘電体層膜厚の条件があること、×印は上記条件が満たされないことを示す。 In the table, ○ mark that thickness conditions of the dielectric layers of the upper and lower layers to satisfy the [Delta] R ≧ 15% and .DELTA.A ≧ 5% is present with a wide enough film Atsuiki (e.g. ± 5% or more), △ mark [Delta] R ≧ 15% and that there is a dielectric layer thickness of conditions satisfying the ΔA ≧ 5%, × mark indicates that the condition is not met.

【0035】 [0035]

【表4】 [Table 4]

【0036】この評価から、Au反射層の膜厚を15n [0036] From this evaluation, 15n the film thickness of the Au reflective layer
m以下に選べば本発明の目的とする記録媒体を構成できることが示された。 It has been shown capable of constituting a recording medium for the purpose of choose if the invention below m.

【0037】(実施例4)実施例1、2、3と同様のことをガラス基板でも行い、同様の結果を得た。 [0037] (Example 4) carried out in a glass substrate to a same manner as in Examples 1, with similar results.

【0038】(実施例5)実施例2において同様の評価を内周部(線速度10m/s)でも行った。 [0038] it was carried out, even the inner peripheral portion of the same evaluation (Example 5) Example 2 (linear velocity 10 m / s). 周波数は6.5MHz(f1)と2.4MHz(f2)である。 Frequency is 6.5MHz (f1) and 2.4MHz (f2).
外周部と同様No. As with the outer peripheral portion No. 2,No. 2, No. 3が50dB以上のCN 3 is 50dB or more of the CN
比と26dBを越える広いパワー幅を示した。 It showed a broad power range in excess of the ratio and 26 dB. また、N In addition, N
o. o. 3の媒体も50dB以上のCN比と26dBを越える消去率を示したが、パワー幅が狭かった。 3 medium also showed erasure rate exceeding 50dB or more CN ratio and 26dB, but the power range was narrow.

【0039】(実施例6)Ge−Sb−Te3元合金の組成をGe−Sb−Teの3角組成座標上でGe [0039] (Example 6) Ge-Sb-Te3 the composition of the binary alloy Ge-Sb-Te Ge on triangular composition coordinate 2 Sb 2 2 Sb 2
Te 5組成とGeSb 4 Te 7組成とSb単体組成を結ぶ範囲で様々に変化して光学定数を調べ、これに基づいて計算及び試作評価を行ったがSb濃度が40%以下の組成では上記Ge 2 Sb 2 Te 5を用いた場合とほぼ同様の領域で本発明の記録媒体が構成可能であることが分かった。 Te 5 examined variously changed in optical constant in a range linking the composition and GeSb 4 Te 7 composition and Sb alone composition, the Ge in the calculations and trial evaluating the composition was but Sb concentration below 40% go on this basis recording medium of the present invention in substantially the same region with the case of using 2 Sb 2 Te 5 was found to be configurable.

【0040】 [0040]

【発明の効果】本発明によって、大きなCN比、高い消去率ならびにその広いパワー許容幅(マージン)を有する記録媒体ならびにその設計方法が提供された。 The present invention, large CN ratio, a recording medium and a method of designing a high erasure ratio and the wider power tolerance (margin) is provided.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図2】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図3】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図4】本発明の1実施例において。 [4] In one embodiment of the present invention. 記録媒体を構成する記録層の厚さと透過率の関係を示す図 It shows the relationship between the thickness and the transmittance of the recording layer of the recording medium

【図5】従来の相変化光記録媒体の構成を示す断面図 5 is a sectional view showing the structure of a conventional phase change optical recording medium

【図6】従来例の実施例中に記載されている記録媒体の有するCN比および消去率と光吸収率差ΔAとの関係をグラフ化した図 6 is a diagram showing a graph of a relationship between the CN ratio and erasing ratio and the light absorptivity difference ΔA with the recording medium described in the examples of the prior art

【図7】従来例の実施例中に記載されている記録媒体の有する反射率変化量ΔRと光吸収率差ΔAとの関係をグラフ化した図 7 is a diagram graph of the relationship between the reflectance change amount ΔR and the light absorptance difference ΔA with the recording medium described in the examples of the prior art

【符号の説明】 DESCRIPTION OF SYMBOLS

1 基板 2 記録層 3 誘電体層 4 光反射層 5 保護板 6 基板 7 第1の誘電体層 8 記録層 9 第2の誘電体層 10 反射層 11 レーザ光線 12 接着層 13 保護層 1 substrate 2 recording layer 3 dielectric layer 4 the light reflecting layer 5 protective plate 6 substrate 7 first dielectric layer 8 recording layer 9 second dielectric layer 10 reflecting layer 11 the laser beam 12 adhesive layer 13 protective layer

フロントページの続き (72)発明者 長田 憲一 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 西内 健一 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Of the front page Continued (72) inventor Kenichi Nagata Osaka Prefecture Kadoma Oaza Kadoma 1006 address Matsushita Electric Industrial Co., Ltd. in the (72) inventor Kenichi Nishiuchi Osaka Prefecture Kadoma Oaza Kadoma 1006 address Matsushita Electric Industrial Co., Ltd. in

Claims (8)

    【特許請求の範囲】
  1. 【請求項1】基板上に、少なくとも第1の誘電体薄膜層、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶相と相対的に小であるアモルファス相との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層、第2の誘電体薄膜層、膜厚が15nm以下であるA 【請求項1】基板上に、少なくとも第1の誘電体薄膜層、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大であるrecording layer comprising a reversibly changing phase change material thin film optical properties between the crystal phase and the amorphous phase is relatively small, the second dielectric thin film layer, the film thickness is 15nm or less a
    uまたはAuを主成分とする合金薄膜層から成る反射層を積層してなる書換え可能な光学的情報記録媒体。
  2. 【請求項2】波長λの照射レーザ光線の内で上記記録層で吸収される比率(以降吸収率と呼ぶ)ならびに上記記録媒体から反射される比率(以降反射率と呼ぶ)を上記記録層がアモルファス相である場合にはそれぞれA(am 2. A (hereinafter referred to as a absorption rate) ratio is absorbed by the recording layer of the irradiated laser beam having a wavelength λ and the recording layer the ratio (hereinafter referred to as a reflectivity) reflected from said recording mediumアモルファス相である場合にはそれぞれA(am
    o)およびR(amo)、また記録層が結晶状態である場合にはそれぞれA(cry)およびR(cry)として、2つの状態間での吸収率の差ΔA(=A(cry)−A(amo))および反射率の差ΔR(=R(cry)−R(amo))がΔA≧5%およびΔR≧15%の2条件を同時に満足する請求項1記載の光学的情報記録媒体。 o) and R (amo), and as each when the recording layer is in the crystalline state A (cry) and R (cry), the difference in absorptivity between the two states ΔA (= A (cry) -A (amo)) and reflectance differences ΔR (= R (cry) -R (amo)) is an optical information recording medium according to claim 1, wherein at the same time satisfying the two conditions of .DELTA.A ≧ 5% and ΔR ≧ 15%.
  3. 【請求項3】反射層がAuを主成分としAl,Cr,C Wherein the reflective layer is mainly composed of Au Al, Cr, C
    u,Ge,Co,Ni,Mo,Ag,Pt,Pd,C u, Ge, Co, Ni, Mo, Ag, Pt, Pd, C
    o,Ta,Ti,Bi,Sbからなる材料群から選ばれる少なくとも1種との合金であることを特徴とする請求項1記載の光学的情報記録媒体。 o, Ta, Ti, Bi, optical information recording medium according to claim 1, characterized in that an alloy of at least one selected from the group of materials consisting of Sb.
  4. 【請求項4】ΔAが10%以上でである請求項1記載の光学的情報記録媒体。 4. The optical information recording medium according to claim 1, wherein ΔA is 10% or more.
  5. 【請求項5】ΔRが20%以上でである請求項1記載の光学的情報記録媒体。 5. An optical information recording medium according to claim 1, wherein ΔR is at least 20%.
  6. 【請求項6】誘電体薄膜層をZnS−SiO 2混合物、 6. A dielectric thin film layer ZnS-SiO 2 mixture,
    記録層をGe−Sb−Te3元合金とし、記録層の厚さを40nm以下とした請求項1記載の光学的情報記録媒体。 The recording layer is Ge-Sb-Te3 binary alloy, the optical information recording medium according to claim 1, wherein the thickness of the recording layer was 40nm or less.
  7. 【請求項7】誘電体材料薄膜をZnS−SiO 2 、記録層をGe−Sb−Teとし、記録層の厚さを25nm以下とした請求項1記載の光学的情報記録媒体。 7. A dielectric material thin film ZnS-SiO 2, the recording layer was Ge-Sb-Te, the optical information recording medium according to claim 1, wherein the thickness of the recording layer was 25nm or less.
  8. 【請求項8】基板上に、少なくとも第1の誘電体薄膜層、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶相と相対的に小であるアモルファス相との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層、第2の誘電体薄膜層、膜厚が15nm以下であるA 8. A substrate at least a first dielectric thin film layer, the optical constants of the above wavelength lambda by irradiation of a laser beam having a wavelength lambda (refractive index n, extinction coefficient k) is a relatively large recording layer comprising a reversibly changing phase change material thin film optical properties between the crystal phase and the amorphous phase is relatively small, the second dielectric thin film layer, the film thickness is 15nm or less a
    uまたはAuを主成分とする合金薄膜層から成る反射層を積層してなる書換え可能な光学的情報記録媒体に波長λの照射レーザ光線を照射したとき、上記記録層で吸収される比率(以降吸収率と呼ぶ)ならびに上記記録媒体から反射される比率(以降反射率と呼ぶ)を上記記録層がアモルファス相である場合にはそれぞれA(amo)およびR(amo)、また記録層が結晶状態である場合にはそれぞれA(cry)およびR(cry)として、2つの状態間での吸収率の差ΔA(=A(cry)−A(amo))および反射率の差ΔR(=R(cry)−R(amo))がΔA≧5%およびΔR≧ When irradiated with irradiated laser beam having a wavelength λ in a rewritable optical information recording medium formed by laminating a reflective layer composed of an alloy thin-film layer mainly composed of u or Au, a ratio that is absorbed by the recording layer (hereinafter each ratio is reflected from the absorption rate and referred) and the recording medium (hereinafter referred to as a reflectivity) when the recording layer is an amorphous phase a (amo) and R (amo), also recording layer is crystalline state as each a (cry) and R (cry) if it is, the difference in absorptivity between the two states ΔA (= a (cry) -A (amo)) and the difference in reflectance ΔR (= R ( cry) -R (amo)) is ΔA ≧ 5% and ΔR ≧
    15%の2条件を同時に満足するように各層の厚さを光学計算を設計する方法であって、 上記記録層、第1および第2の誘電体薄膜層の厚さd Of each layer so as simultaneously to satisfy 15% of the 2 conditions thickness A method of designing an optical calculation, the recording layer, the thickness of the first and second dielectric thin film layer d
    0、d1、d2をそれぞれその光学的厚みを最大λ/2の範囲で様々に仮定してマトリクス法によって入射光の内で上記相変化物質薄膜層に吸収される割合(光吸収率A)、媒体表面から反射される割合(反射率R)を上記相変化物質薄膜がアモルファス状態である場合と、結晶状態である場合の双方について算出し、上記2条件を満たすd0、d1,d2の組合せを求める書換え可能な光学的情報記録媒体の設計方法。 0, d1, the proportion that is absorbed into the phase change material thin film layer among the incident light by variously assuming matrix method in d2 each range the optical thickness of up to lambda / 2 (light absorptance A), and if the ratio (reflectance R) the phase change material thin film is an amorphous state that is reflected from the medium surface, was calculated for both the case where the crystalline state, a combination of the two conditions are satisfied d0, d1, d2 design method of a rewritable optical information recording medium to be obtained.
JP9760692A 1992-04-17 1992-04-17 The optical information recording medium and the structure design method thereof Expired - Fee Related JP3087433B2 (en)

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US08045876 US5424106A (en) 1992-04-17 1993-04-15 Optical information recording medium and method of designing its structure
EP19930106103 EP0566107B1 (en) 1992-04-17 1993-04-15 Optical information recording medium and method of designing its structure
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JPH07320298A (en) * 1994-05-20 1995-12-08 Nec Corp Phase changing type optical disk
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US5681632A (en) * 1995-02-13 1997-10-28 Matsushita Electric Industrial Co., Ltd. Optical information recording medium
US6087067A (en) * 1997-04-10 2000-07-11 Tdkcorporation Optical recording medium
US6268034B1 (en) 1998-08-05 2001-07-31 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus
US6343062B1 (en) 1997-09-26 2002-01-29 Matsushita Electric Industrial Co., Ltd Optical disk device and optical disk for recording and reproducing high-density signals
US6388984B2 (en) 1997-08-28 2002-05-14 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and its recording and reproducing method
US6456584B1 (en) 1998-05-15 2002-09-24 Matsushita Electric Industrial Co., Ltd. Optical information recording medium comprising a first layer having a phase that is reversibly changeable and a second information layer having a phase that is reversibly changeable
US6503690B1 (en) 1997-08-12 2003-01-07 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, method for producing the same, and method for recording and reproducing optical information
US6821707B2 (en) 1996-03-11 2004-11-23 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
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EP1858712B1 (en) 2005-03-17 2010-05-12 Ricoh Company, Ltd. Two-layered optical recording medium

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JPH07320298A (en) * 1994-05-20 1995-12-08 Nec Corp Phase changing type optical disk
US5681632A (en) * 1995-02-13 1997-10-28 Matsushita Electric Industrial Co., Ltd. Optical information recording medium
JPH0973660A (en) * 1995-09-06 1997-03-18 Nec Corp Optical information recording medium and in-recording verifying method
US6821707B2 (en) 1996-03-11 2004-11-23 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
US7037413B1 (en) 1996-03-11 2006-05-02 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
US6087067A (en) * 1997-04-10 2000-07-11 Tdkcorporation Optical recording medium
US6503690B1 (en) 1997-08-12 2003-01-07 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, method for producing the same, and method for recording and reproducing optical information
US6388984B2 (en) 1997-08-28 2002-05-14 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and its recording and reproducing method
US6343062B1 (en) 1997-09-26 2002-01-29 Matsushita Electric Industrial Co., Ltd Optical disk device and optical disk for recording and reproducing high-density signals
US6456584B1 (en) 1998-05-15 2002-09-24 Matsushita Electric Industrial Co., Ltd. Optical information recording medium comprising a first layer having a phase that is reversibly changeable and a second information layer having a phase that is reversibly changeable
US6268034B1 (en) 1998-08-05 2001-07-31 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus

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